C-Reactive Protein Levels and the Risk of Incident Cardiovascular and Cerebrovascular Events in Patients with Obstructive Sleep Apnea.

PURPOSE: Patients with obstructive sleep apnea (OSA) are at increased risk of cardiovascular and cerebrovascular disease (CVD) but it is unclear who are at greatest risk. We determined whether the inflammatory marker, C-reactive protein (CRP), could be a useful prognostic biomarker. METHODS: Adult patients referred for polysomnography (PSG) with OSA were studied. Serum CRP levels were measured using ELISA the morning after PSG. Validated CV events within 4 years of PSG were ascertained by linking to provincial research datasets. RESULTS: 155 patients with OSA (AHI ≥ 5/h) had CRP measured. Median age was 53 and median AHI was 21/h. 10 patients (7.1%) suffered at least one event, but rates varied substantially by CRP (0/35 patients in the lowest quartile, and 7/39 in the highest CRP quartile). In the unadjusted analysis, patients in the highest CRP quartile (≥ 2.38 mg/L) were significantly more likely to suffer an event (odds ratio = 9.72 (95% CI 2.43-38.84), p = 0.001). CRP continued to be a significant predictor after controlling for multiple confounders. OSA severity and desaturation were not significantly associated with prospective events. CONCLUSIONS: In this small preliminary study, OSA patients with an elevated CRP were significantly more likely to suffer a CVD event in the 4 years after PSG. Although these findings need to be confirmed in larger prospective cohorts, CRP may be useful in risk stratifying OSA patients to guide therapy or to identify patients that might be most appropriate for clinical trials of CVD prevention.

The reliability of short-term measurement of heart rate variability during spontaneous breathing in people with chronic obstructive pulmonary disease.

BACKGROUND: Reduced heart rate variability (HRV), a marker of autonomic system dysfunction, has been reported in patients with chronic obstructive pulmonary disease (COPD). Yet, limited data exists on the reliability of HRV measurement in this population. Here we investigated the reliability of short-term HRV measurement performed during spontaneous breathing in patients with COPD. METHODS: Thirteen individuals (8 males) with moderate-to-severe COPD (FEV1 46±16% predicted; FEV1/FVC 49±13) underwent standard time and frequency domain HRV measurements derived from 5-minute electrocardiograms collected on two separate days using a SphygmoCor device. Absolute and relative reliability was assessed by a number of coefficients including within-subject random variation, systematic change in the mean, and retest correlations. RESULTS: Within-subject coefficients of variation (CV) ranged from 4.3% to 193.4%. The intraclass correlation coefficients (ICCs) ranged from 0.72 to 0.93 for parameters related to overall HRV, and from 0.57 to 0.59 for those related to parasympathetic tone in both time and frequency domains. Mean heart rate was the only parameter that showed excellent absolute and relative reliability (CV=4.3%, ICC=0.93). CONCLUSION: The HRV measurements showed overall moderate-to-substantial reliability during spontaneous breathing in COPD population. Our findings support the use of HRV parameters for diagnosis and cardiac risk assessment, but only mean heart rate can be used reliably for monitoring changes in autonomic status following rehabilitation intervention in this population.

Wood smoke exposure induces a pulmonary and systemic inflammatory response in firefighters.

Epidemiological studies report an association between exposure to biomass smoke and cardiopulmonary morbidity. The mechanisms for this association are unclear. The aim of the present study was to characterise the acute pulmonary and systemic inflammatory effects of exposure to forest fire smoke. Seasonal forest firefighters (n = 52) were recruited before and/or after a day of fire-fighting. Exposure was assessed by questionnaires and measurement of carbon monoxide levels (used to estimate respirable particulate matter exposure). The pulmonary response was assessed by questionnaires, spirometry and sputum induction. Peripheral blood cell counts and inflammatory cytokines were measured to define the systemic response. Estimated respirable particulate matter exposure was high (peak levels >2 mg x m(-3)) during fire-fighting activities. Respiratory symptoms were reported by 65% of the firefighters. The percentage sputum granulocytes increased significantly from 6.5 to 10.9% following fire-fighting shifts, with concurrent increases in circulating white blood cells (5.55x10(9) to 7.06x10(9) cells x L(-1)) and band cells (0.11x10(9) to 0.16x10(9) cells x L(-1)). Serum interleukin (IL)-6, IL-8 and monocyte chemotactic protein-1 levels significantly increased following fire-fighting. There were no changes in band cells, IL-6, and IL-8 following strenuous physical exertion without fire-fighting. There was a significant association between changes in sputum macrophages containing phagocytosed particles and circulating band cells. In conclusion, acute exposure to air pollution from forest fire smoke elicits inflammation within the lungs, as well as a systemic inflammatory response.

Particulate matter induces cytokine expression in human bronchial epithelial cells.

The present study was designed to determine cytokines produced by primary human bronchial epithelial cells (HBECs) exposed to ambient air pollution particles (EHC-93). Cytokine messenger RNA (mRNA) was measured using a ribonuclease protection assay and cytokine protein production by enzyme-linked immunosorbent assay. Primary HBECs were freshly isolated from operated lung, cultured to confluence, and exposed to 10 to 500 microg/ml of a suspension of ambient particulate matter with a diameter of less than 10 microm (PM(10)) for 2, 8, and 24 h. The mRNA levels of leukemia inhibitory factor (LIF), granulocyte macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-1alpha, and IL-8 were increased after exposure to PM(10), and this increase was dose-dependent between 100 (P < 0.05) and 500 (P < 0.05) microg/ml of PM(10) exposure. The concentrations of LIF, GM-CSF, IL-1beta, and IL-8 protein measured in the supernatant collected at 24 h increased in a dose- dependent manner and were significantly higher than those in the control nonexposed cells. The soluble fraction of the PM(10) (100 microg/ml) did not increase these cytokine mRNA levels compared with control values and were significantly lower compared with HBECs exposed to 100 microg/ml of PM(10) (LIF, IL-8, and IL-1beta; P < 0.05), except for GM-CSF mRNA (P = not significant). We conclude that primary HBECs exposed to ambient PM(10) produce proinflammatory mediators that contribute to the local and systemic inflammatory response, and we speculate that these mediators may have a role in the pathogenesis of cardiopulmonary disease associated with particulate air pollution.

Cytokines involved in the systemic inflammatory response induced by exposure to particulate matter air pollutants (PM(10)).

Elevated levels of ambient particulate matter (PM(10)) have been associated with increased cardiopulmonary morbidity and mortality. We previously showed that the deposition of particles in the lung induces a systemic inflammatory response that includes stimulation of the bone marrow. This marrow response is related to mediators released by alveolar macrophages (AM) and in this study we measured cytokines produced by human AM exposed to ambient particles of different composition and size. Identified cytokines were also measured in the circulation of healthy young subjects exposed to air pollutants during the 1997 Southeast Asian forest fires. Human AM were incubated with particle suspensions of residual oil fly ash (ROFA), ambient urban particles (EHC 93), inert carbon particles, and latex particles of different sizes (0.1, 1, and 10 microm) and concentrations for 24 h. Tumor necrosis factor-alpha (TNF-alpha) increases in a dose-dependent manner when AM were exposed to EHC 93 particles (p < 0.02). The TNF response of AM exposed to different sizes of latex particles was similar. The latex (158 +/- 31%), inert carbon (179 +/- 32%), and ROFA (216 +/- 34%) particles all show a similar maximum TNF response (percent change from baseline) whereas EHC 93 (1,020 +/- 212%, p < 0.05) showed a greater maximum response that was similar to lipopolysaccharide (LPS) 1 microg/ml (812 +/- 320%). Macrophages incubated with an optimal dose of EHC 93 particles (0.1 mg/ml) also produce a broad spectrum of other proinflammatory cytokines, particularly interleukin (IL)-6 (p < 0.01), IL-1 beta (p < 0.05), macrophage inflammatory protein-1 alpha (MIP-1 alpha) (p < 0.05), and granulocyte macrophage colony-stimulating factor (GM-CSF) (p < 0.01) with no difference in concentrations of the anti-inflammatory cytokine IL-10 (p = NS). Circulating levels of IL-1 beta, IL-6, and GM-CSF were elevated in subjects exposed to high levels of PM(10) during an episode of acute air pollution. These results show that a range of different particles stimulate AM to produce proinflammatory cytokines and these cytokines are also present in the blood of subjects during an episode of acute atmospheric air pollution. We postulate that these cytokines induced a systemic response that has an important role in the pathogenesis of the cardiopulmonary adverse health effects associated with atmospheric pollution.

Effect of mechanical deformation of neutrophils on their CD18/ICAM-1-dependent adhesion.

Mechanical deformation of polymorphonuclear leukocytes (PMN) changes their expression of the surface adhesion molecule CD11b/CD18. We tested the hypothesis that mechanical deformation of PMN enhances their adhesiveness. Purified human PMN were deformed through either 5- or 3-microm polycarbonate membrane filters and allowed to adhere to 96-well plates coated with human recombinant intercellular adhesion molecule-1 (ICAM-1). Flow cytometric studies showed that deformation of PMN increased CD11b/CD18 expression (P < 0.01). PMN adhesion to ICAM-1-coated plates was dependent on the magnitude of cell deformation (5 microm, 63.8 +/- 8.1%, P < 0.04; 3 microm, 232.4 +/- 20.9%, P < 0.01). Priming of PMN (0.5 nM N-formyl-methionyl-leucyl-phenylalanine) before deformation (5 microm) increased PMN adhesion (63.8 +/- 8.1 vs. 105.3 +/- 16.4%; P < 0.04). Stimulation (5% zymosan-activated plasma) of PMN after deformation resulted in increased adhesion, and the degree of increase was dependent on the magnitude of PMN deformation (stimulation, 50.6 +/- 4%; 5-microm filtration and stimulation, 62.9 +/- 6.6%; 3-microm filtration and stimulation, 249.9 +/- 24.2%; P < 0.01). This study shows that mechanical deformation of PMN causes an increase in PMN adhesiveness to ICAM-1 that was enhanced by both priming of PMN before deformation and stimulation after cell deformation.

Interleukin-6 changes deformability of neutrophils and induces their sequestration in the lung.

Interleukin-6 (IL-6) is an important mediator of both the hepatic and the bone marrow components of the acute-phase response. Previous studies from our laboratory have shown that cells released into the circulation from the marrow preferentially sequester in the lung. The present study was designed to examine the mechanism of this sequestration using a single dose of recombinant human IL-6 to stimulate the marrow in rabbits. Marrow release was monitored by labeling polymorphonuclear leukocyte (PMN) precursors in the marrow with the thymidine analogue, 5'-bromo-2-deoxyuridine (BrdU), 24 h before IL-6 treatment. This treatment caused a neutrophilia that was associated with the increase of circulating BrdU- labeled PMN (PMN(BrdU)) and morphometric studies confirmed that PMN(BrdU) released from the marrow preferentially sequestered in the lung microvessels compared to unlabeled PMN. IL-6 treatment increases PMN F-actin content (p < 0.05) that was not due to cell activation by IL-6. In vitro studies show that IL-6 treatment decreased the deformability of circulating PMN (p < 0.05). These studies confirm that IL-6 treatment causes an accelerated release of PMN from the bone marrow and shows that these newly released PMN have high levels of F-actin, are less deformable, and preferentially sequester in lung microvessels.

The effect of repeated exposure to particulate air pollution (PM10) on the bone marrow.

Studies have shown that exposure to ambient particulate matter is related to an increased cardiopulmonary morbidity and mortality. The present study was designed to measure the effect of repeated exposure to urban air particles (PM10) on the rate of production and release of polymorphonuclear leukocytes (PMN) from the bone marrow into the peripheral blood. Rabbits exposed to PM10 (5 mg) twice a week for 3 wk, were given a bolus of 5'-bromo-2'-deoxyuridine (BrdU) to label dividing cells in the marrow that allows us to calculate the transit time of PMN in the bone marrow mitotic and postmitotic pools. The PM10 exposure (n = 8) causes a persistent increase in circulating band cells (p < 0.05) and a shortening of the transit time of PMN through the postmitotic pool in the marrow (64.4 +/- 2.2 h to 56.3 +/- 2.2 h, p < 0.05) if compared with vehicle-exposed control subjects (n = 6). PM10 exposure increases the bone marrow pool of PMN particularly the mitotic pool of PMN (p < 0.05). The PM10 were distributed diffusely in the lung and caused a mild mononuclear inflammation. The percentage of alveolar macrophages containing PM10 correlated significantly with the bone marrow PMN pool size (total pool r2 = 0.56, p < 0.012, mitotic pool r2 = 0.61, p < 0.007) and the transit time of PMN through the postmitotic pool (r2 = -0.42, p < 0.043). We conclude that repeated exposure to PM10 stimulates the bone marrow to increase the production of PMN in the marrow and accelerate the release of more immature PMN into the circulation. The magnitude of these changes was related to the amount of particles phagocytosed by alveolar macrophages.

Interleukin-6 induces demargination of intravascular neutrophils and shortens their transit in marrow.

Recombinant human interleukin-6 (IL-6) causes both a thrombocytosis and leukocytosis. The thrombocytosis is caused by an accelerating thrombocytopoiesis, but the mechanism of the leukocytosis is unknown. This study was designed to determine the relative contributions of marrow stimulation and intravascular demargination to the IL-6 induced neutrophilia. IL-6 (2 microgram/kg), administered intravenously to rabbits, caused a biphasic neutrophilia with an initial peak at 3 h and a second peak at 9 h. Using the thymidine analog 5'-bromo-2'-deoxyuridine (BrdU) to label dividing polymorphonuclear leukocytes (PMNs) in the bone marrow, we showed that IL-6 treatment mobilizes PMNs from the marginated pool into the circulating pool at 2-6 h with a decrease in L-selectin expression on PMNs and also accelerates the release of PMNs from the postmitotic pool in the bone marrow at 12-24 h. We have concluded that IL-6 causes a biphasic neutrophilia wherein the first peak results from the mobilization of PMNs into the circulating pool from the marginated pool and the second peak results from an accelerated bone marrow release of PMNs.

Phagocytosis of particulate air pollutants by human alveolar macrophages stimulates the bone marrow.

Epidemiologic studies have shown an association between the level of ambient particulate matter < 10 microm (PM(10)) and cardiopulmonary mortality. We have shown that exposure of rabbits to PM(10) stimulates the bone marrow. In this study, we determined whether human alveolar macrophages (AMs) that phagocytose atmospheric PM(10) produce mediators capable of stimulating the bone marrow. AMs incubated with PM(10) for 24 h produced tumor necrosis factor-alpha in a dose-dependent manner (86.8 +/- 53.29 pg/ml with medium alone; 1,087.2 +/- 257.3 pg/ml with 0.1 mg/ml of PM(10); P < 0.02). Instillation of the supernatants from AMs incubated with 0.1 mg/ml of PM(10) into the lungs of rabbits (n = 6) increased circulating polymorphonuclear leukocyte (PMN) and band cell counts as well as shortened the PMN transit time through the bone marrow (87.9 +/- 3.3 h) compared with unstimulated human AMs (104.9 +/- 2.4 h; P < 0.01; n = 5 rabbits). The supernatants from rabbit AMs incubated with 0.1 mg/ml of PM(10) (n = 4 rabbits) caused a similar shortening in the PMN transit time through the bone marrow (91.5 +/- 1.6 h) compared with human AMs. We conclude that mediators released from AMs after phagocytosis of PM(10) induce a systemic inflammatory response that includes stimulation of the bone marrow.

Endothelin-1 changes polymorphonuclear leukocytes' deformability and CD11b expression and promotes their retention in the lung.

Endothelin (ET)1 influences polymorphonuclear leukocyte (PMN)- endothelial cell interactions. The aim of this study was to examine the effect of ET-1 on factors that influence PMN-endothelial interaction and retention in the lung both in vitro and in vivo. In vitro, high concentration of ET-1 (> or = 10(-8) M) rapidly increased PMN F-actin content (10(-7) M: 58 +/- 6% increase, P<0.01), whereas lower concentration of ET-1 (< or = 10(-9) M) caused a small but consistent decrease in F-actin content (10(-10) M: 6.9+/-1.5% decrease, P< 0.01). Preincubation of PMNs with the nitric oxide donor sodium nitroprusside (SNP) inhibited the F-actin content increase by 10(-7) M of ET-1 (P<0.01), and enhanced the F-actin content decrease by 10(-10) M of ET-1 (P<0.01). Preincubation of PMNs with Nomega-nitro-L-arginine methylester prevented the F-actin content decrease by 10(-10) M of ET-1. ET-1 (10(-7) M) reduced the deformability of PMNs (P<0.01), which was inhibited by preincubation of PMNs with SNP (P<0.05). ET-1 (10(-9) to 10(-7) M) increased CD11b expression of PMNs (P<0.01), which was inhibited by preincubation of PMNs with SNP. In vivo studies showed that the retention of PMNs treated with ET-1 increased from 45+/-8 to 70+/-5% compared with naive PMNs during their first pass through the lung (P<0.05). We conclude that ET-1 changes the F-actin content, the deformability, and the CD11b expression of PMNs in a dose-dependent fashion and that this leads to increased PMN sequestration in pulmonary microvessels.

Neutrophils released from the bone marrow by granulocyte colony-stimulating factor sequester in lung microvessels but are slow to migrate.

Inflammatory mediators such as granulocyte colony-stimulating factor (G-CSF) release polymorphonuclear leukocytes (PMNL) from the bone marrow. This growth factor is used to promote the host response to infection but its effect on the behaviour of leukocytes at the inflammatory site is unclear. This study examined the sequestration and migration of PMNL released from the bone marrow by G-CSF in a model of streptococcal pneumonia. Eight hours following the administration of either human G-CSF (n=6) or saline (n=3) in rabbits, a focal Streptococcus pneumoniae pneumonia was induced and the animals were followed for 2 h. The thymidine analogue 5'-bromo-2'-deoxyuridine (BrdU) was used to label PMNL (PMNL(BrdU)) in the marrow and as a marker of PMNL newly released by the bone marrow. The PMNL(BrdU) in the lung and blood were identified using immunohistochemistry. G-CSF pretreatment elevated the circulating PMNL (3.6+/-0.4 (mean+/-SEM) to 8.3+/-1X10(9) x L(-1), p<0.05) and PMNL(BrdU) (5.4+/-2.1 to 12.5+/-3.1%, p<0.05) counts at 8 h with little further increase caused by the subsequent 2 h pneumonia. These counts did not change in the control group. Morphometric studies of the lung showed that the total number of PMNL sequestered in lung capillaries were increased in the G-CSF group and the percentage of the these PMNL that were BrdU-labelled, was higher than in circulating blood (p<0.05). In the G-CSF group, only 11.2+/-2.6% of the PMNL that migrated into the airspaces were PMNL(BrdU) compared to 50.8+/-8% PMNL(BrdU) in the pulmonary capillaries. In vitro studies showed PMNL(BrdU) released from the bone marrow by G-CSF are less deformable than unlabelled circulating PMNL (p<0.01). It is concluded that granulocyte colony-stimulating factor treatment causes the marrow to release polymorphonuclear leukocytes that preferentially sequester in lung microvessels but are slow to migrate out of the vascular space into the airspace at the pneumonic site.

The response of human bone marrow to chronic cigarette smoking.

Chronic cigarette smoking in humans causes leukocytosis. Animal studies show that chronic smoking shortens the transit time of polymorphonuclear leukocytes (PMNLs) through the bone marrow. The present study examines the response of human bone marrow to chronic cigarette smoking. Three characteristics of peripheral blood PMNLs that indicate active bone marrow release (band cell counts, surface L-selectin expression and myeloperoxidase (MPO) content), were measured in 38 healthy chronic smokers (23+/-5 pack-yrs) and 15 age- and sex-matched nonsmoking controls. The total white cell (6.8+/-0.3x10(9) versus 5.3+/-0.2x10(9) cells x L(-1), p<0.0001) and PMNL (4.2+/-0.18x10(9) versus 3.2+/-0.1x10(9) cells x L(-1), p<0.003) counts were higher in smokers as were the percentage (4.8+/-0.6 versus 1.1+/-0.2, p<0.0001) and total number (0.21+/-0.04x10(9) versus 0.03+/-0.001x10(9) cells x L(-1), p<0.01) of band cells. Flow cytometry showed that the mean fluorescence intensity (MFI) of L-selectin (3.2+/-0.2 versus 2.6+/-0.1, p<0.05) on PMNLs was higher in smokers. There was no difference in the baseline or N-formyl-methionyl-leucyl-phenylalanine-stimulated expression of CD63 or CD18/CD11b (surface markers of PMNL activation) between smokers and controls. The MPO content of PMNLs was higher in smokers (3.4+/-0.3 versus 1.7+/-0.2 MFI, p<0.05). Smokers with a low (<75% of the predicted value) diffusing capacity of the lung for carbon monoxide had higher PMNL MPO levels than smokers with a diffusing capacity of >75% pred (p<0.05). In conclusion, chronic smoking causes phenotypic changes in circulating polymorphonuclear leukocytes that are characteristic of chronic stimulation of the bone marrow and it is speculated that the increased number of immature polymorphonuclear leukocytes contributes to the chronic lung inflammation associated with cigarette smoking.

The human bone marrow response to acute air pollution caused by forest fires.

Atmospheric pollution increases cardiopulmonary morbidity and mortality by unexplained mechanisms. Phagocytosis of fine particles (PM(10)) by rabbit alveolar macrophages elevates white blood cells (WBC) by releasing precursors from the bone marrow and this could contribute to the pathogenesis of cardiopulmonary disease. The present study examined the association between acute air pollution caused by biomass burning and peripheral WBC counts in humans. Serial measurements of the WBC count made during the 1997 Southeast Asian Smoke-haze (Sep 29, Oct 27) were compared with a period after the haze cleared (Nov 21, Dec 5) using peripheral blood PMN band cells to monitor marrow release. The results showed that indices of atmospheric pollution were significantly associated with elevated band neutrophil counts expressed as a percentage of total polymorphonuclear leukocytes (PMN), with maximal association on zero and 1 lag day for PM(10) and 3, and 4 lag days for SO(2) (p value < 0.000). We conclude that atmospheric pollution caused by biomass burning is associated with elevated circulating band cell counts in humans because of the increased release of PMN precursors from the marrow. We speculate that this response contributes to the pathogenesis of the cardiorespiratory morbidity associated with acute air pollution.

Interleukin 8 (IL-8) and the release of leukocytes from the bone marrow.

Interleukin 8 (IL-8) is produced by various cells upon stimulation and influences a variety of functions of leukocytes in particular neutrophils. Systemic administration of IL-8 induces a rapid neutropenia associated by sequestration of neutrophils in the lung that is followed by a neutrophilia characterized by the rapid release of neutrophils from the bone marrow. These cells are released predominantly from the bone marrow venous sinusoids. In addition, several studies have shown the potential role of IL-8 in hematopoiesis and trafficking of hematopoietic stem cells. Systemic administration of IL-8 induces a rapid mobilization of progenitors from the bone marrow with long-term myelo-lymphoid repopulation capacity. It has been employed clinically to mobilize hematopoietic progenitor cells into the peripheral blood and used for autologous or allogeneic bone marrow transplantation. The mechanism for these effects of IL-8 is largely speculative. This report summarizes current ideas on the possible mechanisms how IL-8 influences cell trafficking in and from the bone marrow.

Partial liquid ventilation with perfluorocarbon in acute lung injury: light and transmission electron microscopy studies.

Liquid ventilation using perfluorocarbon has been shown to improve gas exchange in animal models of acute lung injury as well as in children with acute respiratory distress syndrome. This study was designed to define structural features of lung injury following partial liquid ventilation (PLV) using light and transmission electron microscopy in a rabbit model of acute respiratory distress. Animals were treated with either conventional mechanical ventilation (CMV-gas) (n = 6) or PLV (n = 5) for 4 h after the induction of acute lung injury with saline lavage. Control animals were killed after the lung injury. PLV significantly improved alveolar-arterial oxygen tension and the oxygen index compared with CMV (P < 0.05). Morphometric studies using light microscopy show less alveolar hemorrhage, less edema, and fewer hyaline membranes in the PLV group (P < 0.05). Polymorphonuclear leukocyte sequestration in lung capillaries (11.4 +/- 1.5 versus 19.2 +/- 3 x 10(8)/ml, P < 0.05, PLV versus CMV) and migration into airspaces (3.1 +/- 1.2 versus 4.5 +/- 1.1 x 10(8)/ml, P < 0.05, PLV versus CMV) were lower in the gravity-dependent lung regions. There were fewer alveolar macrophages in the PLV group compared with other groups (P < 0.05). Fluorescence microscopy analysis shows fewer type II alveolar epithelial cells in the CMV group and brighter type II cells in the PLV group. Transmission electron microscopy studies show more alveolar wall damage in the CMV group, with type II cells detached from their basement membrane with fewer surfactant-containing lamellar bodies. We conclude that quantitative histologic analysis shows less lung damage and inflammation when perfluorocarbon is combined with CMV in the management of acute respiratory distress syndrome.

Polymorphonuclear leukocytes released from the bone marrow by granulocyte colony-stimulating factor: intravascular behavior.

INTRODUCTION: Granulocyte-colony stimulating factor (G-CSF) treatment stimulates the bone marrow and releases polymorphonuclear leukocytes (PMN) into the circulation. This study was designed to measure the intravascular margination, demargination and survival of PMN released from the marrow by G-CSF. MATERIALS AND METHODS: To trace PMN in the circulation, dividing PMN in the bone marrow of rabbits were labeled with 5'-bromo-2'-deoxyuridine (BrdU) and the effects of a single dose of G-CSF (12.5 microg/kg) on the behavior of these labeled cells in the circulation were measured. RESULTS: The results show that G-CSF induced a granulocytosis that peaked 12 h after treatment. This granulocytosis was associated with stimulation of the bone marrow characterized by shortening of the transit time of PMN through the marrow (97.3+/-2.5 h n=4 control vs 78.9+/-3.6 h n=5 G-CSF) particularly in the post-mitotic pool (P<0.01). Morphometric studies of the lung show a reduced sequestration of BrdU-labeled PMN in lung microvessels in G-CSF-treated animals (P<0.05) and a approximately 14-fold (G-CSF-group) vs a approximately 65-fold (control-group) enrichment of BrdU-labeled PMN in lung tissue if compared to circulating blood. The effect of G-CSF on demargination of PMN was measured by transferring BrdU-labeled PMN from donor animals treated with G-CSF to recipients. G-CSF did not cause demargination of intravascular PMN but delayed the clearance of G-CSF-treated PMN in the circulation. This delayed clearance was associated with inhibition of apoptosis in circulating PMN when measured both by morphology (17.7+/-2.3 vs 7.5+/-1.4%, P<0.01) and flow cytometry (16.2+/-1.1 vs 5+/-1.9%, P<0.01) using a DNA end-labeling method (control vs G-CSF group). CONCLUSION: We conclude that PMN released from the bone marrow by G-CSF sequestered less in the lung microvessels and have a prolonged intravascular life span.

Emphysematous pyelonephritis: case report and review of the literature.

Emphysematous pyelonephritis (EP), a rare necrotizing infection of the upper urinary tract, is a life-threatening complication of patients with diabetes mellitus. A case of EP is described where the diagnosis was delayed for 36 h and the patient died notwithstanding aggressive medical and surgical intervention. The demonstration of gas in the renal structures is pathognomonic of EP. Because early diagnosis and aggressive medical and surgical management is imperative for recovery, we recommend plain abdominal radiographs as a minimal screening tool for all diabetic patients who present to hospital with a presumptive pyelonephritis. The diagnosis should also be considered in patients who failed appropriate medical therapy.